Having two good seamers is good enough. The tendency to think we need 3 pacers is a mindset issue which we need to overcome. Even if the wicket is conducive for pace bowling, the limited skills of our pacers mean they will never be able to exploit it (Anyway it is rare to see three seamers finish their quota of 30 overs). So we might as well play three quality spinners. Actually we are lucky because Shakib and is an allrounder we will be able to field such a combination. If you are still not convinced learn from Pakistan. They have enough of pace bowlers to play 3-4 of them in a game. But why wont they do that? Because they know other teams will stutter against their spin- Ajmal, Abdur Rehman, Hafeez, Afridi. So they play 3 spinners in most games-ODI, Test or T20.

So maybe this is a lineup we should focus on developing-if we want to win i.e, not just compete